A survey of the reproductive biology in Italian branchiopods

A survey of the most important aspects of the reproductive biology of Lepidurus apus lubbocki Brauer, 1873 (Notostraca) is presented. Gametogenesis, germ cell distribution, and somatic tract structure of the male gonad are studied by means of TEM and SEM. The most important data emerging from our observations is the total and widespread degeneration of the sperms. We discuss the real functionality of male germ cells, and the implications on sexuality and reproductive strategies. On the whole, present ultrastructural observations suggest that males of Lepidurus apus lubbocki are not functional. Therefore, we suggest that this form reproduces parthenogenetically as the functional female gonad lacks any associated testicular cells. For comparison, we analyzed the male portion of the hermaphroditic gonad of Triops longicaudatus (LeConte, 1846) from California. In this case functionallity of the testis lobes and sperm were readily apparent.     

Scapharca inaequivalvis tetrameric hemoglobin A and B chains: cDNA sequencing and genomic organization

A and B globin cDNAs from the tetrameric hemoglobin of the bivalve molluscScapharca inaequivalvis were isolated by RT-PCR and sequenced. When compared with the biochemical data, the deduced protein sequences revealed only one amino acid substitution in the B chain. In order to investigate the genomic structure of these invertebrate globin genes, their intronic regions were amplified by PCR. The two genes showed the typical two-intron/three-exon organization found in vertebrates and seemed to reflect the ancestral gene structure, in accordance with the new globin gene evolution theory proposed by Dixon and Pohajadak (Trends Biochem. Sci. 17:486–488, 1992). The alternative hypothesis suggested by Go (Nature 291:90–92, 1981), that the central intron was lost during evolution, is also considered. In contrast to the related clamAnadara trapezia, S. inaequivalvis A and B globin genes were found to be present in multiple copies differing in intron size. In this study we report the complete sequences of the A (1,471 bp) and B (2,221 bp) globin genes, giving a detailed analysis of their intron features.     

Telocytes in Crohn's disease

Crohn's disease (CD) is a relapsing chronic inflammatory disorder that may involve all the gastrointestinal tract with a prevalence of terminal ileum. Intestinal lesions have a characteristic discontinuous and segmental distribution and may affect all layers of the gut wall. Telocytes (TC), a peculiar type of stromal cells, have been recently identified in a variety of tissues and organs, including gastrointestinal tract of humans and mammals. Several roles have been proposed for TC, including mechanical support, spatial relationships with different cell types, intercellular signalling and modulation of intestinal motility. The aim of our study was to investigate the presence and distribution of TC in disease‐affected and ‐unaffected ileal specimens from CD patients compared with controls. TC were identified by CD34/PDGFRα immunohistochemistry. In affected CD specimens TC disappeared, particularly where fibrosis and architectural derangement of the intestinal wall were observed. In the thickened muscularis mucosae and submucosa, few TC entrapped in the fibrotic extracellular matrix were found. A discontinuous network of TC was present around smooth muscle bundles, ganglia and enteric strands in the altered muscularis propria. At the myenteric plexus, the loss of TC network was paralleled by the loss of interstitial cells of Cajal network. In the unaffected CD specimens, TC were preserved in their distribution. Our results suggest that in CD the loss of TC might have important pathophysiological implications contributing to the architectural derangement of the intestinal wall and gut dysmotility. Further functional studies are necessary to better clarify the role of TC loss in CD pathophysiology.     

Glucoamylase by recombinant Kluyveromyces lactis cells: production and modelling of a fed batch bioreactor

A cultural system, aimed at the production of glucoamylase with cells of a non-conventional yeast transformed for the enzyme expression, Kluyveromyces lactis JA6-GAA was realised. Glucoamylase production was accomplished in a reactor operating in fed batch mode to avoid limitations with respect to oxygen transfer, and achieve high cell density. A mathematical model able to describe batch and fed batch operations was developed. The theoretical and experimental approach permitted to catch sight of possible physiological changes in the producer strain and set up a suitable fed-batch run to achieve a higher cell density.     

Reevaluation of Production of Paralytic Shellfish Toxin by Bacteria Associated with Dinoflagellates of the Portuguese Coast

Paralytic shellfish toxins (PSTs) are potent neurotoxins produced by certain dinoflagellate and cyanobacterial species. The autonomous production of PSTs by bacteria remains controversial. In this study, PST production by two bacterial strains, isolated previously from toxic dinoflagellates, was evaluated using biological and analytical methods. Analyses were performed under conditions determined previously to be optimal for toxin production and detection. Our data are inconsistent with autonomous bacterial PST production under these conditions, thereby challenging previous findings for the same strains.